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Three polyoxygenated bipyrrole alkaloids were isolated from the aerial of Speranskia tuberculata, including two new compounds, speranberculatines B (1) and C (2), along with a known compound, speranskatin A (3). Their structures were identified via NMR-spectroscopic and MS analyses. None of them showed activity in inhibiting the production of NO in LPS-induced RAW264.7 cells.

Abstract Vast efforts have been devoted to the development of antifungal drugs targeting the cell wall, but the supramolecular architecture of this carbohydrate-rich composite remains insufficiently understood. Here we compare the cell wall structure of a fungal pathogen Aspergillus fumigatus and four mutants depleted of major structural polysaccharides. High-resolution solid-state NMR spectroscopy of intact cells reveals a rigid core formed by chitin, β-1,3-glucan, and α-1,3-glucan, with galactosaminogalactan and galactomannan present in the mobile phase. Gene deletion reshuffles the composition and spatial organization of polysaccharides, with significant changes in their dynamics and water accessibility. The distribution of α-1,3-glucan in chemically isolated and dynamically distinct domains supports its functional diversity. Identification of valines in the alkali-insoluble carbohydrate core suggests a putative function in stabilizing macromolecular complexes. We propose a revised model of cell wall architecture which will improve our understanding of the structural response of fungal pathogens to stresses.

Hydration is one of the most significant issues for combat sports as athletes often use water restriction for quick weight loss before competition. It appears that alkaline water can be an effective alternative to sodium bicarbonate in preventing the effects of exercise-induced metabolic acidosis. Therefore, the main aim of the present study was to investigate, in a double blind, placebo controlled randomized study, the impact of mineral-based highly alkaline water on acid-base balance, hydration status, and anaerobic capacity. Sixteen well trained combat sport athletes (n = 16), were randomly divided into two groups; the experimental group (EG; n = 8), which ingested highly alkaline water for three weeks, and the control group (CG; n = 8), which received regular table water. Anaerobic performance was evaluated by two double 30 s Wingate tests for lower and upper limbs, respectively, with a passive rest interval of 3 minutes between the bouts of exercise. Fingertip capillary blood samples for the assessment of lactate concentration were drawn at rest and during the 3rd min of recovery. In addition, acid-base equilibrium and electrolyte status were evaluated. Urine samples were evaluated for specific gravity and pH. The results indicate that drinking alkalized water enhances hydration, improves acid-base balance and anaerobic exercise performance.

Background It is well known that salinization (high-pH) has been considered as a major environmental threat to agricultural systems. The aim of this study was to investigate the differences between salt stress and alkali stress in metabolic profiles and nutrient accumulation of wheat; these parameters were also evaluated to determine the physiological adaptive mechanisms by which wheat tolerates alkali stress. Results The harmful effect of alkali stress on the growth and photosynthesis of wheat were stronger than those of salt stress. High-pH of alkali stress induced the most of phosphate and metal ions to precipitate; as a result, the availability of nutrients significantly declined. Under alkali stress, Ca sharply increased in roots, however, it decreased under salt stress. In addition, we detected the 75 metabolites that were different among the treatments according to GC-MS analysis, including organic acids, amino acids, sugars/polyols and others. The metabolic data showed salt stress and alkali stress caused different metabolic shifts; alkali stress has a stronger injurious effect on the distribution and accumulation of metabolites than salt stress. These outcomes correspond to specific detrimental effects of a highly pH environment. Conclusions Ca had a significant positive correlation with alkali tolerates, and increasing Ca concentration can immediately trigger SOS Na exclusion system and reduce the Na injury. Salt stress caused metabolic shifts toward gluconeogenesis with increased sugars to avoid osmotic stress; energy in roots and active synthesis in leaves were needed by wheat to develop salt tolerance. Alkali stress (at high pH) significantly inhibited photosynthetic rate; thus, sugar production was reduced, N metabolism was limited, amino acid production was reduced, and glycolysis was inhibited.

The pH of the soil in relation to the availability of plant nutrients has been an important research topic in soil fertility and plant nutrition. In the 1930 and 1940 s, a diagram was proposed that showed how the availability of major and minor nutrients was affected by the pH. This conceptual diagram, developed by Emil Truog based on earlier work, included 11 nutrients. The width of the band at any pH value indicated the relative availability of the plant nutrient. The band did not present the actual amount, as that was affected by other factors such as the type of crop, soil and fertilization. For the 11 nutrients on the diagram, a pH of around 6.5 was considered most favorable. The diagram has been often published in text books and soil extension material and continues to be reproduced. This paper reviews how the diagram was developed, and what its limitations are. In recent decades, research in soil fertility and plant nutrition has focused on the biological transformations of plant nutrients in the soil and it has been recognized that the soil pH influences solubility, concentration in soil solution, ionic form, and adsorption and mobility of most plant nutrients. Nutrients interact and different plants respond differently to a change in pH. The soil pH cannot be used to predict or estimate plant nutrient availability, and the diagram should not be used as it suffers from numerous exceptions and barely represents any rules.

Investigating slow earthquake activity in subduction zones provides insight into the slip behavior of megathrusts, which can provide important clues about the rupture extent of future great earthquakes. Using the S-net ocean-bottom seismograph network along the Japan Trench, we mapped a detailed distribution of tectonic tremors, which coincided with very-low-frequency earthquakes and a slow slip event. Compiling these and other related observations, including repeating earthquakes and earthquake swarms, we found that the slow earthquake distribution is complementary to the Tohoku-Oki earthquake rupture. We used our observations to divide the megathrust in the Japan Trench into three along-strike segments characterized by different slip behaviors. We found that the rupture of the Tohoku-Oki earthquake, which nucleated in the central segment, was terminated by the two adjacent segments.

Background Graft survival after kidney transplantation has significantly improved within the last decades but there is a substantial number of patients with declining transplant function and graft loss. Over the past years several studies have shown that metabolic acidosis plays an important role in the progression of Chronic Kidney Disease (CKD) and that alkalinizing therapies significantly delayed progression of CKD. Importantly, metabolic acidosis is highly prevalent in renal transplant patients and a recent retrospective study has shown that metabolic acidosis is associated with increased risk of graft loss and patient death in kidney transplant recipients. However, no prospective trial has been initiated yet to test the role of alkali treatment on renal allograft function. Methods The Preserve-Transplant Study is an investigator-initiated, prospective, patient-blinded, multi-center, randomized, controlled phase-IV trial with two parallel-groups comparing sodium bicarbonate to placebo. The primary objective is to test if alkali treatment will preserve kidney graft function and diminish the progression of CKD in renal transplant patients by assesing the change in eGFR over 2 years from baseline. Additionally we want to investigate the underlying pathomechanisms of nephrotoxicity of metabolic acidosis. Discussion This study has the potential to provide evidence that alkali treatment may slow or reduce the progression towards graft failure and significantly decrease the rate of end stage renal disease (ESRD), thus prolonging long-term graft survival. The implementation of alkali therapy into the drug regimen of kidney transplant recipients would have a favorable risk-benefit ratio since alkali supplements are routinely used in CKD patients and represent a well-tolerated, safe and cost-effective treatment. Trial registration ClinicalTrials.gov NCT03102996 . Trial registration was completed on April 6, 2017.

There is an abrupt transition from alkaline to acid soil pH when mean annual precipitation exceeds mean annual potential evapotranspiration, demonstrating that climate creates a nonlinear pattern in soil solution chemistry at the global scale. Climate creates a global threshold in soil chemistry Soil pH affects nutrient supply and storage in soils and, in consequence, can influence plant productivity. Transitions from alkaline to acid soils are caused by variations in the water balance across natural climate gradients, but a global-scale investigation of the influence of climate on soil pH is lacking. Here Eric Slessarev et al . evaluate the global relationship between water balance and soil pH, and find that there is an abrupt transition from alkaline to acid soil pH that occurs where mean annual precipitation begins to exceed mean annual potential evapotranspiration. The authors suggest that deviations from the observed global pattern may result from seasonality, climate history, erosion and mineralogy. Soil pH regulates the capacity of soils to store and supply nutrients, and thus contributes substantially to controlling productivity in terrestrial ecosystems 1 . However, soil pH is not an independent regulator of soil fertility—rather, it is ultimately controlled by environmental forcing. In particular, small changes in water balance cause a steep transition from alkaline to acid soils across natural climate gradients 2 , 3 . Although the processes governing this threshold in soil pH are well understood, the threshold has not been quantified at the global scale, where the influence of climate may be confounded by the effects of topography and mineralogy. Here we evaluate the global relationship between water balance and soil pH by extracting a spatially random sample ( n  = 20,000) from an extensive compilation of 60,291 soil pH measurements. We show that there is an abrupt transition from alkaline to acid soil pH that occurs at the point where mean annual precipitation begins to exceed mean annual potential evapotranspiration. We evaluate deviations from this global pattern, showing that they may result from seasonality, climate history, erosion and mineralogy. These results demonstrate that climate creates a nonlinear pattern in soil solution chemistry at the global scale; they also reveal conditions under which soils maintain pH out of equilibrium with modern climate.

MOGNO is the micro and nano tomography dedicated beamline at Sirius, operating at three specific energies: 21.5, 39.0, and 67.7 keV. Its optics is composed by a set of three mirrors (pre-KB + KB set), delivering a 3 mrad cone beam, coming from a 100x100 nm 2 main source. The pre-KB mirror must be aligned to produce a secondary source of 0.3 x 800.0 µm 2 , however, such an alignment is challenging, as deviations from it produce adverse effects on the beamline’s main source, enlarging it. Moreover, to evaluate a nanofocus a novel strategy is required. Here, it is proposed to use the fluorescence signal from a thin Au line deposited on a Si substrate scanning in the focus region along the horizontal plane, making it possible to visualize the beam’s caustic. Furthermore, it is possible to evaluate the focus size, via the analysis of the gradient of the caustic along the direction perpendicular to beam propagation. Using the described strategy, it was possible to measure a focus size of 603±103 nm and 668 ± 114 nm , limited by control issues experienced during measurements.